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Miller's langur

Miller's langur is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Miller's langur rather than just read about it. In short: Miller's langur (Presbytis canicrus), also known as Miller's grizzled langur or Kutai grey langur, is a species of leaf monkey. It is endemic to East Kalimantan on the island of Borneo in Indonesia.

Miller's langur — main illustration
Miller's langur — illustration

Key takeaways

  • Miller's langur belongs to biology; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Miller's langur to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Miller's langur from memory before moving on to harder problems.

Reference excerpt

Miller's langur (Presbytis canicrus), also known as Miller's grizzled langur or Kutai grey langur, is a species of leaf monkey. It is endemic to East Kalimantan on the island of Borneo in Indonesia. It is one of the world's most endangered primates, and was at one time thought to be extinct, until it was rediscovered in 2012.

Taxonomy Miller's langur is a leaf monkey within the family Cercopithecidae and subfamily Colobinae. It was formerly considered a subspecies of Hose's langur, Presbytis hosei (as Presbytis hosei canicrus). It was split from P. hosei on the basis of different morphology by primatologists Colin Groves and Christian Roos.

Distribution and habitat Miller's langur is native to the island of Borneo in the province of East Kalimantan in Indonesia. It lives in dipterocarp rainforests up to an elevation of about 1,000 metres (3,300 ft).

Description Miller's langur ranges from 48 centimetres (19 in) to 56 centimetres (22 in) long excluding tail and has a tail length ranging from 65 centimetres (26 in) to 84 centimetres (33 in). Males weigh from 6 kilograms (13 lb) to 7 kilograms (15 lb) while females weight between 5.5 kilograms (12 lb) and 6 kilograms (13 lb). The fur on its back is gray with a grizzly appearance, and the fur on its belly is whitish. The upper part of its face is black while the lower part of its face is whitish, with the whitish part forming a U shape below the nose. It has a brown crown at the top of its head. Infants are white with a black cross on their backs.

Habits A majority of Miller's langur's diet comes from young leaves and leaf shoots, and their next most important food item is unripe fruit. It also consumes other items such as eggs, seeds and flowers. It typically lives in groups ranging from 5 to 12 animals including a single adult male, with an average group size of 8 monkeys. Non-group males are solitary. It is sympatric with two other leaf monkeys from the genus Presbytis, the maroon leaf monkey and the white-fronted surili. It is known to utilize salt licks along with sympatric maroon leaf monkeys. It is arboreal and diurnal, and spends a majority of its time in the mid to upper canopy of the forest.

Conservation status Miller's langur is listed as endangered by the IUCN due primarily to habitat loss, fragmentation and hunting. It is one of the rarest primates in Borneo. With little information available, it was thought to be extinct several times. In 2012, a team of international scientists rediscovered it in Wehea Forest in East Kalimantan, Borneo, disproving its extinction. Wehea Forest is outside Miller's langur's previously known range, which was primarily Kutai National Park to the south of Wehea. The scientists used mineral licks and cameras to show that the species still exists, and had difficulty identifying it from the photos since so few photos previously existed. Limited to a geographical range from the central coast of East Kalimantan to the Kutai National Park, the species is highly regarded as an endemic and extremely vulnerable primate. Experts speculate it becoming extinct in the very near future, due to multiple factors such as deforestation and overhunting for its bezoar stones and as a food source. The bezoar stones, which are smooth, hard mineral deposits found in the digestive tracts of some animals, are used as good luck charms, and also for its alleged ability to neutralize some poisons, but only occur in a minority of the monkeys. Although Miller's langur is protected under Indonesian law, the legal protections may be ineffective because it is listed under a defunct scientific name, P. aygula. In October of 2019, Forrest Galante led an expedition and recorded the first video evidence of a Miller's langur in the 21st century.

References

External links Media related to Presbytis canicrus at Wikimedia Commons

Illustrations

Miller's langur illustration
Miller's langur illustration
Miller's langur illustration

Worked examples

Example 1 — a first encounter with Miller's langur

Start with the simplest possible case. Write down what Miller's langur claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Miller's langur before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Miller's langur ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Miller's langur

In research
Miller's langur appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Miller's langur in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Miller's langur is common in secondary-school and first-year university syllabi. It links to neighbouring topics Arboreal mammals, Endangered fauna of Asia, Endemic fauna of Borneo, so understanding it makes those chapters shorter.
In everyday life
Look for Miller's langur outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
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How to study Miller's langur in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Miller's langur means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Miller's langur out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Miller's langur in simple terms?

Miller's langur (Presbytis canicrus), also known as Miller's grizzled langur or Kutai grey langur, is a species of leaf monkey. It is endemic to East Kalimantan on the island of Borneo in Indonesia.

Why does Miller's langur matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Miller's langur?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Miller's langur.

Tags

  • Arboreal mammals
  • Endangered fauna of Asia
  • Endemic fauna of Borneo
  • Endemic fauna of Indonesia
  • IUCN Red List endangered species
  • Mammals described in 1934
  • Presbytis
  • Primates of Borneo
  • Primates of Indonesia
  • Taxa named by Gerrit Smith Miller Jr.

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